Function merge_unified_page 

async fn merge_unified_page(
    remote: Result<(Vec<LibraryAsset>, bool), String>,
    page: u32,
    ui: &Rc<LibraryWindowUi>,
    query: Option<&str>,
) -> Result<(Vec<LibraryAsset>, bool), String>

Merge a page of remote API assets with local files that haven’t been synchronized yet.